title: Operational definitions of sarcopenia and their associations with 5-year changes in falls risk in community-dwelling middle-aged and older adults.
abstract: Sarcopenia may be diagnosed in the clinic using operational definitions based on low muscle mass or function. This prospective, population-based study revealed that sex-specific associations may exist between operational definitions of sarcopenia and falls in community-dwelling middle-aged and older adults.
  
  
  BACKGROUND
  The objective of this study is to verify associations between sarcopenia and falls risk and to determine changes in sarcopenia prevalence over 5 years in middle-aged and older men and women according to different anthropometric and performance-based operational definitions.
  
  
  METHODS
  N = 681 volunteers (48% female; mean ± SD age 61.4 ± 7.0 years) participated in baseline and follow-up assessments (mean 5.1 ± 0.5 years later). Appendicular lean mass (ALM) was assessed by dual-energy X-ray absorptiometry, hand grip (HGS) and lower-limb (LLS) strength were assessed by dynamometry, and falls risk was determined using the physiological profile assessment. Anthropometric definitions (ALM/height squared [ALM-H], ALM/weight × 100 and a residuals method [ALM-R]) and performance-based definitions (HGS, LLS and upper- and lower-limb muscle quality [LMQ]) of sarcopenia were examined. The lowest 20% of the sex-specific distribution for each definition at baseline was classified as sarcopenia.
  
  
  RESULTS
  Sarcopenia prevalence increased after 5 years for all operational definitions except ALM-H (men: -4.0%; women: -5.5%). Men classified with sarcopenia according to anthropometric definitions, and women classified with sarcopenia according to performance-based definitions, had significant increases in falls risk over 5 years (all P < 0.05) compared to individuals without sarcopenia. Significant sex interactions were observed for ALM-R, LLS and LMQ (all P < 0.05) definitions.
  
  
  CONCLUSIONS
  Sarcopenia prevalence generally increases at a higher rate when assessed using performance-based definitions. Sarcopenia is associated with increases in falls risk over 5 years in community-dwelling middle-aged and older adults, but sex-specific differences may exist according to different anthropometric or performance-based definitions.
authors.affiliation: NorthWest Academic Centre, The University of Melbourne, Western Health, St Albans, 3021, VIC, Australia, d.scott@unimelb.edu.au.
authors.forename: D
authors.initials: D
authors.lastname: Scott
authors.forename: A
authors.initials: A
authors.lastname: Hayes
authors.forename: K M
authors.initials: KM
authors.lastname: Sanders
authors.forename: D
authors.initials: D
authors.lastname: Aitken
authors.forename: P R
authors.initials: PR
authors.lastname: Ebeling
authors.forename: G
authors.initials: G
authors.lastname: Jones
mesh_terms: D000058:Accidental Falls / Q000706:statistics & numerical data*; D000368:Aged; D000886:Anthropometry / Q000379:methods; D001823:Body Composition / Q000502:physiology; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology; D015995:Prevalence; D011446:Prospective Studies; D012111:Residence Characteristics; D012307:Risk Factors; D055948:Sarcopenia / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D012737:Sex Factors; D013648:Tasmania / Q000453:epidemiology